It is not even a year since Jaylen Smith was learning the power of the youth vote as a student government leader at his high school in Arkansas. Now the pioneering teenager is about to put his knowledge into practice as the youngest elected Black mayor anywhere in the US.

On Tuesday, as the Georgia Senate runoff was capturing the attention of the nation, Smith, 18, was steadily amassing the votes he needed to become the next leader of the small city of Earle, population 1,785.

“You have to start somewhere, you really do,” Smith, who graduated from Earle high school last summer after three years as Student Government Association president, told the Washington Post.

“I didn’t want to be 30 or 40 and become a mayor when I could be one right now.”

Smith, who lives at home with his parents, said his mother could not stop crying about his success, which came with a 235-183 vote defeat of Nemi Matthews, the city’s street and sanitation superintendent.

Matthews was one of the first to offer his best wishes, writing: “I congratulate mayor-elect Jaylen Smith for a well ran race, I wish you well.”

Smith credited younger voters, having proved his credentials to them by negotiating a deal with a high school cafeteria vendor, among other issues.

“I worked time after time to get them what they wanted,” he said, adding that his achievements in school matters had made him “passionate and determined” to serve the wider community.

While not the first 18-year-old to become an elected mayor – an honor that fell to Michael Sessions in Hillsdale, Michigan, in 2005 – Smith is the youngest Black candidate to achieve the feat.

“I’m excited for Jaylen and the entire community in Earle as he becomes the youngest-ever African American mayor elected in the country,” Frank Scott Jr, mayor of Little Rock, Arkansas, and president of the African American Mayors’ Association, told CNN.

“I’m proud of his willingness to enter into public service at such a young age and his aspirational goals for the city.”

Smith said he consulted several mayors across the state before his campaign, and thanked them for their guidance. In his own message posted to Facebook, he said it was “time to build a better chapter” for his city.

Among his first orders of business after he is sworn in next month, Smith said, would be to move the city’s police department to 24-hour operation. Other policy goals include ridding Earle of abandoned homes, creating jobs for city youth and providing transportation for elderly or infirm residents to grocery stores.

Smith was set to return to Earle high school on Thursday, for a celebration of what supporters billed as “a monumental moment for our town”.